There are currently in use in Australia seal devices for this purpose comprising an apertured base member including a non-metallic apertured flange element of resilient material bonded in face-to-face relation to a continuous peripheral metallic flange, and a sleeve member of resilient material integral with the base member and which extends outwardly therefrom to receive the elongate member. The base member is in use secured to the non-planar surface, and is of a non-resilient manually deformable nature so that, in use, it may be deformed to conform to the contour of the non-planar surface and will substantially retain such deformed contour. The sleeve member has an end remote from the base member which is adapted to receive said elongate member in sealing engagement therewith when the seal device is in use. The sleeve member, between the said remote end thereof and the base member, is sufficiently flexible to accommodate in use misalignment between the base member and the remote end of the sleeve, that may arise during installation or during the service life of the seal device.
The seal device above referred to is described in more detail in U.S. Pat. No. 4,333,660 in the name of G. M. Cupit. This seal device is very effective when used for pipes or ducts of a size up to about 400 mm diameter or similarly sized rectangular. However in many applications, as encountered in industrial and commercial building, it is required to seal about large pipes or ducts, as used in ventilation and air conditioning systems, frequently of diameters of 600 mm and above.
When sealing around ducts of this order of size the number of ridges or valleys over which the base member of the seal device may extend is increased. This requires a corresponding increase in the length of material required in the base member edge area to accommodate the degree of contouring necessary for the base member to follow the ridges and valleys. Also the increased degree of contouring in the edge area of the base member produces an increased degree of distortion over the general area of the base flange, and this distortion may extend into the sleeve member itself.
If we consider the prior proposed seal device in a large size, and having a flat rectangular shaped base flange, with a continuous one piece deformable metal strip along the complete marginal edge, the following problems arise in use. When the two opposite edge portions of the base member, which extend transversely across the ribs and valleys of the sheet, are contoured to follow the profile of a roof sheet, the length of these two edge portions is shortened. Consequently the two longitudinally disposed edge portions of the base member are required to move towards one another, as they are rigid at their ends with the ends of the two transverse contoured edge portions. However as the centrally located sleeve member is relatively stiff compared to the flange, the majority of the inward movement is accommodated in distortion of the area of the base flange on either side of the sleeve member.
This can result in folds and pockets in the base flange extending between the ridges of the roof sheet, which functions as a dam to water flow. This damming of the water flow is not acceptable as it aggravates leakage problems, especially in so-called flat and low pitched roofs.
If the sleeve member is made more resilient, so that it may deflect to absorb part of an inward movement of the longitudinal edges, this reduces the maximum size the of duct that may pass through the sleeve member.
Further with the one piece metal strip about the edge portion of the base member, the position of the two side portions of the strip is determined solely by the degree of shortening of the transverse portions of the strip subjected to the contouring. This can result in the side portions being positioned where it is inconvenient or difficult to secure them in sealed contact with the roof sheet. Such a location may be on a fold in the roof sheet, or on a vertical or near vertical side of a ridge or valley.
Similar problems exist if the seal device of the prior art has a circular flange with a continuous metal strip secured thereto along the perimetal marginal portion. The greater the amount of contouring of the strip required to accommodate the ridges and valleys of the roof sheet, the greater is the reduction of the diameter of strip and the degree of folding required of the flange inwardly of the perimetal strip.